Diurnal cycle of convective activity over the West of Central Africa based on Meteosat images

Abstract

The diurnal cycle of deep convective activity over the West of Central Africa was investigated using Meteosat 7 data over a period of 5 years (1998–2002). An index of deep convective activity was built by thresholding to brightness temperatures less than 235K to detect deep convective activity. It was found that deep convection over the contiguous study area has large diurnal variations with considerable regional features. Convective activity over the land exhibits a coherent diurnal cycle characterized by a rapid afternoon buildup, and a more gradual nighttime decrease. Over the sea, the diurnal cycle is weak and peaks around noon. The results of the study suggest that both topography and surface conditions are critical factors in the spatial and temporal patterns of the diurnal cycle of convection.